The invention relates to ovens with catalytic converters for removing airborne grease particles. The invention relates to any type of oven, but is particularly applicable to microwave combination ovens.
It is known to use catalytic converters in ovens in order to flamelessly oxidise oxidisable components in the hot air from the cooking chamber. For example, a recycling oven using such a catalytic converter is described in International Patent Application Number PCT/US98/10736. In this oven hot air from the cooking chamber is passed through a catalytic converter before being returned to the cooking chamber.
One disadvantage of the arrangement described in international application number PCTIUS98/10736 is that daily cleaning is required for the ducting which directs hot air from the cooking chamber to the catalytic converter. A further disadvantage is that the air-flow within the cooking chamber is somewhat uneven.
The present invention seeks to overcome at least some of the disadvantages of the prior art.
According to the invention there is provided an oven comprising a number of chamber walls defining a cooking chamber, heating means for heating food within the cooking chamber, at least one opening in at least one of the chamber walls, fan means for driving air out of the cooking chamber through said opening, a grease filter attached substantially directly to the one of the chamber walls and a catalytic converter located downstream of said grease filter.
It will be appreciated that, because the grease filter is placed close to the cooking chamber, the labour involved in cleaning any ducting leading to the grease filter, required in the prior art, is avoided.
In different embodiments, the catalytic converter is located within 20, 10 or 5 centimeters of said opening.
The catalytic converter may be located substantially immediately adjacent the grease filter.
In a preferred embodiment there are no other components between the catalytic converter and the opening except the grease filter.
Conveniently, the air which is driven out of the cooking chamber is recirculated back into the cooking chamber after passing through the catalytic converter.
The oven may be a microwave combination oven. In such ovens heating of the food is achieved by a combination of microwave energy and electric heating elements.
There may be two such openings each provided with a catalytic converter having the features described above.
In this case, each opening may be provided with a separate fan.
The openings may be provided in opposite side walls of the oven.
An electric heating element may be provided to heat air in the cooking chamber.
The heating element may also be arranged to emit infrared radiation directly onto food within the cooking chamber.
In this case the electric heating element may be provided directly behind one of the chamber walls which is provided with perforations which allow the chamber wall both to transmit infrared radiation from the electric heating element and to reflect microwave radiation back into the cooking chamber.
The oven may further comprise a rotatably driven turntable for rotating food to be cooked within the cooking chamber.
The invention will now be more particularly described, by way of example only, with reference to the accompanying figures, which show two embodiments of microwave combination ovens constructed in accordance with the invention.